Or bury the nuclear waste in oceanic trenches. It is out of the way and future generations won't stumble upon it when humans forget where they buried all this stuff.
It's not about the actual radiation, that's easy to deal with. It's about the containers cracking or leaking and having that stuff floating around in the ocean, contaminating our food and the environment. Even the strongest container we can make is still susceptible to the corrosive effects of the ocean.
If you're going to bury it in the ocean, your best bet would be to bury it near a subduction zone. But then you have the earth itself possibly being the cause of the container cracks and leaks.
Define "know". Do we have it carved in tablets of stone from on high? No. Are we reasonably confident? Yes. There are already hotter things in the ocean (e.g. black smokers). What kind of effects are you worried about?
Is it a big deal if they break/leak? Are there any theoretical problems that I, as not-an-oceanic non-nuclear-waste expert, am not aware of? Not just over 5 or 10 years, but over hundreds of years? Are we able to monitor them for these problems? How difficult or expensive is it to fix any problems?
I ask because I genuinely don't know. I'd be OK with it if scientific consensus and consultation between the ocean and nuke people said we know enough about them to say there aren't issues. I don't want to just say "lets just dump them in a place I don't personally care about that's really far from me".
